324 Mr. Vonlton^s further experiments upon 



Experiment 11. is interesting, in showing that black 

 paper-covered sticks are not nearly so effective in pro- 

 ducing dark larvae as dark twigs, although the latter are 

 less black. At the same time it must be remembered 

 that the former tend to become grey from the growth 

 of mould. 



The comparison between these and the former larvae 

 of this year certainly shows that the results produced 

 in the parent larvae in 1887 were not hereditary. A 

 careful comparison was made on Sept. 14th (see both 

 sets of tables), showing that the larvae descended from 

 those which had been made green (III. in 1887) were not 

 only darker than those descended from larvae which had 

 been made dark (II. in 1887), when both were exposed 

 to conditions which tended towards darkness, but the 

 converse was also true, viz., the larvae of the former set 

 became less green than those of the latter, when both had 

 been subjected to green surroundings. In other words, 

 the tendencies exhibited were rather the reverse of those 

 to be expected by the operation of heredity, and it seems 

 clear that no bias whatever was imparted to the off- 

 spring by the conditions to which the parents had been 

 exposed. 



In addition to these two sets of experiments, another 

 set was conducted in the same year (1888) upon larvae 

 hatched from eggs laid by a captured female. These 

 eggs hatched June 18th and 19th. Thus all the larvae 

 in this set of experiments came from the same parents. 



Dates. 



July 1 

 July 21 



Experiment I. 

 Dark Surroundings. 



45 larvae introduced 

 wlien quite small. 



All had escaped ex- 

 cejit 3 by gnawing holes 

 in the black tissue-pa- 

 per roof to cylinder. 

 Black net substituted, 

 and 12 larvas intro- 

 duced from II. and 

 III., making 27 here. 



EXPEEIMENT II. 



Green Surrounding 

 in dark. 



Experiment III. 

 Green Surroundings, 



45 similar larvae in- I 45 similar larvae in- 

 troduced, troduced. 



34 or 35 larvas alive. 39 larva; alive. Leaves 

 The leaves found to be ; had become verybrown. 

 withered and brown : Larvaj had not become 

 when examined Aug. j green. 

 19. 



